//
// Created by lenovo on 24-12-31.
//

#include <cassert>
#include <cstring>
#include <list>
#include <string>

namespace zzy
{
    template<class T>
    class vector
    {
    public:
        typedef T* iterator;
        typedef const T* const_iterator;

        iterator begin()
        {
            return _start;
        }
        iterator end()
        {
            return _finish;
        }
        const_iterator begin() const
        {
            return _start;
        }
        const_iterator end() const
        {
            return _finish;
        }

        vector()
            :_start(nullptr)
            ,_finish(nullptr)
            ,_endofstorage(nullptr)
        {}
        explicit vector(size_t n, const T& val = T())
        {
            resize(n, val);
        }
        template<class InputIterator>
        vector(InputIterator first, InputIterator last)
        {
            while (first != last)
            {
                push_back(*first);
                ++first;
            }
        }

        vector(const vector<T>& v)
            :_start(nullptr)
            ,_finish(nullptr)
            ,_endofstorage(nullptr)
        {
            reserve(v.capacity());
            for(auto e : v)
            {
                push_back(e);
            }
        }

        vector<T>& operator=(vector<T> v)
        {
            swap(v);
            return *this;
        }

        void swap(vector<T>& v)
        {
            std::swap(_start, v._start);
            std::swap(_finish, v._finish);
            std::swap(_endofstorage, v._endofstorage);
        }


        ~vector()
        {
            if(_start)
            {
                delete[] _start;
                _start = _finish = _endofstorage = nullptr;
            }
        }

        size_t capacity() const
        {
            return _endofstorage - _start;
        }
        size_t size() const
        {
            return _finish - _start;
        }
        T& operator[](size_t pos)
        {
            assert(pos < size());
            return _start[pos];
        }
        const T& operator[](size_t pos) const
        {
            assert(pos < size());
            return _start[pos];
        }

        void reserve(size_t n)
        {
            if(n > capacity())
            {
                size_t sz = size();
                T* tmp = new T[n];
                if(_start)
                {
                    //memcpy(tmp, _start, sizeof(T)*sz);
                    for (size_t i=0; i<sz; i++)
                    {
                        tmp[i] = _start[i];
                    }
                    delete[] _start;
                }
                _start = tmp;
                _finish = _start + sz;
                _endofstorage  = _start + n;
            }
        }

        void push_back(const T& x)
        {
            if(_finish == _endofstorage)
            {
                size_t newcapacity = capacity() == 0? 4 : capacity() * 2;
                reserve(newcapacity);
            }
            *_finish = x;
            ++_finish;
        }

        void insert(iterator pos, const T& x)
        {
            assert(pos >= _start && pos <= _finish);
            if(_finish == _endofstorage)
            {
                size_t len = pos - _start;
                size_t newcapacity = capacity() == 0 ? 4 : capacity() * 2;
                reserve(newcapacity);
                pos = _start + len;
            }
            iterator end = _finish - 1;
            while(end >= pos)
            {
                *(end + 1) = *end;
                --end;
            }
            *pos = x;
            ++_finish;
        }

        iterator erase(iterator pos)
        {
            assert(pos >= _start && pos <= _finish);
            iterator it = pos + 1;
            while(it != _finish)
            {
                *(it -1) = *it;
                ++it;
            }
            --_finish;
            return pos;
        }

        void resize(size_t n, const T& val = T())
        {
            if(n < size())
            {
                _finish = _start + n;
            }
            else
            {
                reserve(n);
                while (_finish != _start + n)
                {
                    *_finish = val;
                    ++_finish;
                }
            }
        }


    private:
        iterator _start;
        iterator _finish;
        iterator _endofstorage;
    };
}

int main()
{
    // zzy::vector<std::string> v;
    // v.push_back("11111");
    // v.push_back("22222");
    // v.push_back("33333");
    return 0;
}